IFX_FOLDVIEW configuration parameter
Use the IFX_FOLDVIEW configuration parameter to enable or disable view folding. For certain situations where a view is involved in a query, view folding can significantly improve the performance of the query. In these cases, views are folded into a parent query instead of the query results being put into a temporary table.
- onconfig.std value
- IFX_FOLDVIEW 1
- values
- 0 or Off = Disables view folding.
1 or On = Default. Enables view folding.
- takes effect
- After you edit your onconfig file and restart the database server.
- When you reset the value dynamically in your onconfig file by running the onmode -wf command.
- When you reset the value in memory by running the onmode -wm command.
Usage
The following types of queries can take advantage of
view folding:
- Views that contain a UNION ALL clause and the parent query includes a regular join, HCL Informix® join, ANSI join, or an ORDER BY clause
A temporary table is created and view folding is not performed
for the following types of queries that perform a UNION ALL operation
involving a view:
- The view has one of the following clauses: AGGREGATE, GROUP BY, ORDER BY, UNION, DISTINCT, or OUTER JOIN (either Informix or ANSI type).
- The parent query has a UNION or UNION ALL clause.